How do I view a temporary table in MySQL?
mysql> CREATE TEMPORARY TABLE t1 (c1 INT PRIMARY KEY) ENGINE=INNODB; Query INNODB_TEMP_TABLE_INFO to view the temporary table metadata. The TABLE_ID is a unique identifier for the temporary table. The NAME column displays the system-generated name for the temporary table, which is prefixed with “#sql”.
Where are MySQL temp tables stored?
An internal temporary table can be held in memory and processed by the MEMORY storage engine, or stored on disk by the InnoDB or MyISAM storage engine. If an internal temporary table is created as an in-memory table but becomes too large, MySQL automatically converts it to an on-disk table.
Can you query a temp table?
Temporary tables are very similar to permanent tables. Permanent tables get created in the database you specify and remain in the database permanently until you delete or drop them. … You can then execute your queries on that temporary table. Temporary tables are stored inside “tempdb” which is a system database.
Do temp tables make queries run faster?
I have often found that temp tables speed things up, sometimes dramatically. The simple explanation is that it makes it easier for the optimiser to avoid repeating work. Of course, I’ve also seen temp tables make things slower, sometimes much slower.
Should I drop temp table in stored procedure?
If you are wondering why it is not required to drop the temp table at the end of the stored procedure, well, it is because when the stored procedure completes execution, it automatically drops the temp table when the connection/session is dropped which was executing it.
How do I check if MySQL is running?
We check the status with the systemctl status mysql command. We use the mysqladmin tool to check if MySQL server is running. The -u option specifies the user which pings the server. The -p option is a password for the user.
What is drawback of JSON columns?
The drawback? If your JSON has multiple fields with the same key, only one of them, the last one, will be retained. The other drawback is that MySQL doesn’t support indexing JSON columns, which means that searching through your JSON documents could result in a full table scan.
Are temporary tables stored in memory?
This all means that temporary tables behave like any other sort of base table in that they are logged, and stored just like them. In practice, temporary tables are likely to remain cached in memory, but only if they are frequently-used: same as with a base table.
What Cannot have a trigger associated with it?
Since triggers execute as part of a transaction, the following statements are not allowed in a trigger: All create commands, including create database, create table, create index, create procedure, create default, create rule, create trigger, and create view. All drop commands. alter table and alter database.